Polyvinylchloride stabilized compositions

ABSTRACT

Novel compositions and a stabilized polyvinyl chloride resin composition comprising essentially, in a predominant amount, a polyvinyl chloride resin and, in a small amount, at least one boron-containing organotin compound having the formula WHEREIN R is a member selected from the group consisting of alkyl alkenyl, aralkyl, alkylaryl and aryl; X1 is a member selected from the group consisting of the residues of monomercapto compounds, dimercapto compounds and polymercapto compounds, said residues containing at least one free sulfhydryl radical; and X2 and X3 are members selected from the group consisting of hydroxyl, the same residues as X1, the residues of carboxylic acids and maleic acid monoesters, and the residues of mercapto compounds containing no free sulfhydryl radical.

Patented Nov. 10, 1970 3,539,529 POLYVINYLCHLORIDE STABILIZED COMPOSITIONS Yohei Kawakami, Osaka-fu, Toshio Seki, Osaka-shi, and

Jozaburo Suzuki, Kobe-shi, Japan, assignors to Nitto Kasei Co., Ltd., Osaka, Japan, a corporation of Japan No Drawing. Continuation-in-part of application Ser. No. 443,657, Mar. 29, 1965. This application Jan. 26, 1968, Ser. No. 700,698

Int. Cl. C08f 45/62 US. Cl. 260-45.75 7 Claims ABSTRACT OF THE DISCLOSURE Novel compositions and a stabilized polyvinyl chloride resin composition comprising essentially, in a predominant amount, a polyvinyl chloride resin and, in a small amount, at least one boron-containing organotin compound having the formula wherein R is a member selected from the group consisting of alkyl, alkenyl, aralkyl, alkylaryl and aryl; X is a member selected from the group consisting of the residues of monomercapto compounds, dimercapto compounds and polymercapto compounds, said residues containing at least one free sulfhydryl radical; and X and X are members selected from the group consisting of hydroxyl, the same residues as X the residues of carboxylic acids and maleic acid monoesters, and the residues of mercapto compounds containing no free sulfhydryl radical.

STABILIZED RESIN COMPOSITIONS This application is a continuation-in-part of US. application Ser. No. 443,657, filed Mar. 29, 1965, now abandoned.

This invention relates to the stabilization of polyvinyl chloride resins against light and heat using certain novel boron-containing organotin compounds. Various stabilizers have been used in the past in the treatment for stabilizing against light and heat polyvinyl chloride (PVC) and the copolymeric resins predominantly thereof. These stabilizers however are as yet unsatisfactory with respect to heat and light resistance. In addition, they are undesirable in that because these stabilizers volatilize and spatter during the heat treatment such as calendering, extruding or moulding of the PVC resins they are a health hazard to the worker.

As a result of having engaged in extensive researches for a stabilizer having better resistance to heat and light than the conventional stabilizers and because of its low volatility would hardly volatilize or spatter during the heat treatment of the foregoing resins so as to a health hazard to the worker, we found that a boron compound having through the intermediary of an organotin at least one sulfhydryl radical (SH radical) in its molecules was very valuable as a stabilizer.

Accordingly, an object of the present invention is to provide a stabilizer having low volatility which is valuable for stabilizing the PVC resins against light and heat. Another object is to provide stabilized PVC resin compositions by means of the use of the foregoing stabilizer.

The foregoing objects of the invention are achieved by the incorporation in the PVC resins in a small amount of at least one boron-containing organotin compound having the formula OSn(R)z-Xa wherein R is a member selected from the group consisting of alkyl, alkenyl, aralkyl, alkylaryl and aryl; X is a member selected from the group consisting of the residues of monomercapto compounds, dimercapto compounds, and polymercapto compounds, said residues containing at least one free sulfhydryl radical; and X and X are members selected from the group consisting of hydroxyl, the same residues as X the residues of carboxylic acid and maleic acid 'monoesters, and the residues of mercapto compounds containing no free sulfhydryl radical.

Preferred for R are alkyl radicals of 1-18 carbon atoms, particularly methyl, ethyl, propyl, butyl, amyl and octyl radicals, and phenyl radical or benzyl radical. As X are used, the residues of the monomercapto compounds of 2-20 carbon atoms such as mercapto acids, e.g., thioglycollic acid, mercaptopropionic acid, thiomalic acid and thiosalicylic acid; the ester of mercapto alcohol and dibasic carboxylic acid, e. g.,

monomercaptoethyl maleate (HOOCCH CHCOOCH CH SH) monomercaptoethyl phthalate (HOOCC H COOCH CH SH) and monomercaptoethyl adipate (HOOOCH CH CH CH COOCH CH SH) the dibasic carboxylic acid and mercapto acid ester of glycol, e.g., ethylene glycol maleate thioglycolate (HOOCCH CHCOOCH CH OOCCH SH) ethylene glycol phthalate thioglycolate (HOOCC6H4COOCHQCHZOOCCHZSH) ethylene glycol succinate thioglycolate (HOOCCH CH COOCH CH OOCCH SH) ethylene glycol maleate mercaptopropionate (HOOOCH CHCOQ'CH CH OOCCHgCHgSH) diethylene glycol maleate mercaptopropionate (HOOCCH=CHCOO-CH CH OCH CH OOCCH CH SH) triethylene glycol maleate mercaptopropionate (HO O=CCH=CHCOOCH CH OCH CH O OCCH CH SH) propylene glycol maleate thioglycolate (HO OCCH=CHCOOCHCH CH OOCCH SH propylene glycol succinate mercaptopropionate (HO OOCH CH COOCHCH CH OOCCH CH SH) and dipropylene glycol phthalate mercaptopropionate (HOOCC H COOCHCH CH OCHCH CH OOCCH CH SH) Further, also used are the residues of dimercapto compounds of 2-20 carbon atoms such as dimercaptans, e.g.,

ethylene dimercaptan, 1,2-propylene dimercaptan, 1,4- tetramethylene dimercaptan, dimercaptoethyl ether,oc,a'- dimercapto-p-xylene; the esters of mercapto alcohol and mercapto acid, e.g.,

mercaptoethyl thioglycolate (HSCH CH O O'CCH SH and mercaptoethyl mercaptopropionate (HSCH CH OOCCH CH SH the esters of mercapto alcohol and dibasic carboxylic acid, e.g.,

dimercaptoethyl maleate HSCH CH O OCH=CHCO OCH CH SH dimercaptoethyl phthalate (HSCH CH OOCC H COOCH CHQSH) and dimercaptoethyl itaconate (HSCH CI-I OOCCCH CH OOOCH CH SH) the esters of glycol and mercapto acid, c.g., ethylene glycol dithioglycolate (HSCH COOCH CH OOCCH SH) propylene glycol dithioglycolate (HSCH COOCHCH CH O OCCH 'SH) diethylene glycol dimercaptopropionate (HSCH CH COOCH CH OCH CH OOCCH CH SH) triethylene glycol dithioglycolate (HSCH COOCH CH OCH CH OCH2CH OOCCH SH) dipropylen glycol dimercaptopropionate (HSCH CH COOCHCH CH OCHCH CH OOOCH CH SH) ethylene glycol dimercaptopropionate (HSCH CH COOCH CH OOCCH CH SH) and propylene glycol dimercaptopropionate (HSCH CH CO OCHCH CH OOOCH CH SH and polythiodimercaptan obtained by reacting sodium disulfide with a mixture of 98 mole percent of bis(2-chloroethyl)-formal and 2 mole percent of trichloropropane, e.g.,

HS (CH CH OCH OCH CH SS 3 CH CH OCH OCH CH SH Further, also used are the residues of polymercapto compounds of 2-20 carbon atoms e.g., glycerin trithioglycolate, glycerin trimercaptopropionate, and trithioglycerol. As X and X besides the same residues as those of X usable are also the residues of octyl acid, lauric acid, stearic acid, maleic acid, oleic acid, benzoic acid, monobutylmaleate, monooctylmaleate, monocetylmaleate, monobenzylmaleate, lauryl mercaptan, thioglycollic acid, mercaptopropionic acid, hexylthioglycolate, butylmercaptopropionate, mercaptoethanol, mercaptoethyl acetate and mercaptoethyl laurate.

The chemical structures of the typical stabilizers, which are valuable in the present invention, are illustrated by means of the following Formulas (l)-(l), wherein R,

R, R" and R' are respectively methyl (CH butyl (C H octyl (C H and phenyl (C H groups.

As regards the process for producing these boroncontaining organotin compounds, the compound of Formula (1) can be obtained, for example, by reacting 1 mole of boric acid, 3 moles of dibutyltin oxide and 3 moles of propylene glycol dithioglycolate.

The hereinbefore presented examples as well as the other boron-containing organotin compounds to be used in the present invention exhibit remarkable effectiveness in stabilizing the polyvinyl chloride resins and hence impart to these resins particularly good resistance to heat and light. In adition, since they are substances having very low volatility, they are very convenient from the standpoint of health management, as they do not have an adverse effect on the human body. While these stabilizers are productive of results with very small amounts, they are normally used suitably in an amount of 0.110 parts by weight per parts by weight of the polyvinyl chloride resins. These stabilizers can be used either singly or as mixtures. They can also "be used conjointly with the conventional stabilizers, antioxidants or ultraviolet absorbers.

The stabilizer compounds which are valuable in this invention are those which contain in their molecules, as indispensable components, the three components of an organotin, a sulfhydryl radical and boron. The other radicals making up the molecules essentially have no effect on the effectiveness of the present invention. The fact that satisfactory results cannot be obtained if any one of the foregoing three indispensable components is missing will be illustrated by the hereinafter given examples. From this fact, it is presumed that the surprising improvements in the resistance to heat and light which are imparted by the invention stabilizer are the result of the superior synergistic effects of these components that are contained in the molecules.

The polyvinyl chloride resins to which the present invention is applicable include the PVC homopolymeric resins, the copolymeric resins predominantly of PVC, and the blends of these resins with other resins. Accordingly, polyvinyl chloride resin in the specification and claims includes all of the aforesaid resins. These resins may also contain the customary fillers, coloring 6 change after heating them for 1 hour at 180 C. As a result, the following decrease in weights occurred in the respective stabilizers: (1) 0.5%, (2) 0.8%, (3) 0.4%, (4) 0.2%, .(5) 0.2%, (6) 0.4%, (7) 0.6%, (8) 0.3%, (9) 0.5%, (10) 0.2%, (11) 1.8%, (12) 5.0%, (13) 4.5%,

agents and other additives. 5 (14) 3.0%. These results indicate the remarkable small- EMMPLES 4 ness of the volatilities of the invention stabilizers. This means not only that the problem which has a great bear- The Previously mentlonhd Orgahohn ing on health hazards during heat treatment is solved but compounds of the Preseht lnventlofl haVlIlg the Formulas 10 also that the offensive odor characteristic of the sulfur )-(10) were separately added 1n amounts of 2 Parts type stabilizers is alleviated. While in the case of the by weight to 100 parts by Weight of PVC P=1100). stabilizer of Formula (1) the decrease in weight was followed by milling for 5 minutes on a mixing roll at 0.5%, that of the stabilizer of Formula ,(14) was 3.0%. 160:2" C. The resulting sheets were tested for their The PVC to which was added as the stabilizer that of resistance to heat by means of a color tone change test 15 Formula (1) did not give off during treatment the in a Geer oven at 180 C., and for their resistance to light offensive odor characteristic of the mercaptans. by means of a color tone change test using an ultraviolet light source of 2537 A. EXAMPLES 15-16 Y Y 0f compaflsoh, thsts ehtlfely the Same as th0$e One mole of boric acid, 3 moles of dibutyltin oxide, described above were carried out using the compounds 2 moles f dimercaptoethyl maleate and 1 mole of havlflg thfl following Formulas D-( Whlch We lauric acid were reacted to yield a compound having syntheslledl the following Formula (15 OS1l(R)2-S (3121325 (15) (ll) BOSn(R)z-S 0 215 25 O"'SI1(C4HO)HSGH2CH2OOCCH=CHCOOOH2CH2SH OSn(R)r-S 0121125 BOSn(C4Hn)a 0112011200CCH=OHCOOCH2CH2SH 03?!) S CHaC O O CHCH3CH2O O C CHISH OSIl(C4H9)g-O O C 011E By way of comparison, a sulfur type stabilizer having 0 119 S CHZOOOCHCH3CH2OOCCH2SH the following Formula (16) was used.

SCHzCOOCHOHaCHzOOOCHzSH 13 B-SCHzCOOCHCHsCHzOOCCHzSH Q EOHWOOCSH" SCHZCOOCHCHZCHzOOCCHZSH and a compound of the following Formula (14), a known C4 9 S CHQCOOCiH" sulfur type stabilizer: (14) 04119 50121125 Three parts by weight of each of these two classes of stabilizers were added respectively to parts by weight of a vinyl chloridevinyl acetate copolymer and after mill- GlHn SCrzHzs 4L0 ing for 5 minutes on a mixing roll at i2 C. the Th results f 1 change f PVC b means f these mixtures were made into sheets. Tests for resistance to tests, as observed with the passage of time, are shown heat and light were conducted, as described in Examples in Table 1. 1-14, with the results shown in Table 11.

TABLE II Resistance to heat test after- Resistance Stabilizer to light test (formula) 0.5 hr. 1.0 hr. 1.5 hrs. 2.0 hrs. after 48 hrs.

(15) Colorless Colorless Colorless Light yellow-, Colorless. (16)* do do Light yellow-..- Yellow Light brown.

*Control.

TABLE I Resistance to heat test after- Resistance Stabilizer to light test (formula) 0.5 hr. 1.0 hr. 1.5 hrs. 2.0 hrs. after 48 hrs.

(1) Colorless Colorless Colorless Light yellow Colorless.

(1 do Light yellow Yellow Do. do o Do. (4) "do do ...do Light yellow Do. do. do Yellow Do. do Colorless Light yellow Do. (7) do do Light yellow ellow Do. (8) do do Colorless Light ye11ow Do. (9). --do rln do do Do. (10) do do Light yellow Yellow Do. (11)* do Light yellow Yellow Light brown. Light brown: (12)*. ight yello Yellow Light brown Brown rown. (13). Colorless Light brown Brown Black Black. (1 9* do Light yellow Yellow Light brown Brown.

Controls.

As the changes in the color tone of PVC which attend its decomposition by heat and light take the course of colorless light yellow yellow light brown brown black, it is apparent from the foregoing results that the stabilizing elfects that are obtained by the invention stabilizers are truly remarkable.

Next, for testing the volatility of each of the stabilizers, the several stabilizers were measured for their weight When the changes in weight were measured in the volatility test after heating the stabilizers for 1 hour at C. in a Geer oven, the decrease in weight of stabilizer (15) was 0.8% while that of stabilizer (16) was 3.5%.

During the treatment when stabilizer (15) was added there was no offensive odor characteristic of the mercaptans.

7 EXAMPLES 17-18 reacted to yield a compound of the following Formula OSn(CeH5)iOO CCHzS H and 2 moles of lauryl mercaptan. 5 O sn(CfiH5)2 OO C CH For comparison, a known sulfur type stab1l1zer of the fol- O-S11(C Hi7)f S CI-IzCOOCHgCHzOOCCH SII lowing Formula (20) was used BOSII(OBHl7)2S C12H25 04H O C O-'SI1(C5H17)2S 0121125 10 \sn/fl 2 For comparison, the previously mentioned known sulfur type stabilizer (14) was used. Two parts by weight of -0112 each of these two classes of stabilizers were added Three parts by weight of each of these two classes of respectively to 100 parts by weight of a vinyl chloride- 1r stabilizers were added respectively to 100 parts by weight vinylidene chloride copolymer and after milling for 5 a of PVC in which had been admixed by weight of minutes on a mixing roll the mixtures were made into chlorinated polyethylene. The mixtures were milled for 5 sheets. The tests for resistance to heat and light were minutes on a mixing roll at 150:2" C. The same tests for conducted, as described in Examples 1-14, with the resistance to heat and light, as described in Examples results shown in Table III. 114, were conducted with the results shown in Table V.

TABLE V Resistance to heat test after- Resistance Stabilizer to light test (formula) 0.5 hr. 1.0 hr. 1.5 hrs. 2.0 hrs. after 48 hrs.

(19) Colorless Colorless Light yellow Yellow Colorless. Light yellow Yellow Light brown Brown Brown.

*Control.

TABLE III Resistance to heat test after- Resistance Stabilizer to light test (formula) 0.5 hr. 1.0 hr. 1.5 hrs. 2.0 hrs. after 48 hrs.

(17) Colorless Colorless Colorless Light yellow Colorless. (14)* .d0 Light yell0w Yellow Light brown. Brown.

*Control.

When the changes in Weight were measured in the When the volatility test was conducted, the measurement volatility test after heating the stabilizers for 1 hour in a of the changes in weight being made after heating the Geer oven at 180 C. the weight decrease of stabilizer stabilizers for 1 hour in a Geer oven at 180 C. stabilizer (17) was 0.4% while that of stabilizer (14) was 3.0%. 4O (19) showed a weight decrease of 0.2% whereas that of EXAMPLES 19 20 stabilizer (20) was 1.0%.

The following Examples 23-36 illustrate typical A compound 9 the f0110W111g F p Was methods of preparing the novel stabilizing compounds of obtained by reacting 1 mole of boric acid, 3 moles of the invention dimethyltin oxide, 1 mole of propylene glycol dithio- EXAMPLE 23 l colate 1 mole of monobenz l maleate and 1 mole of g y 62 gms. boric acid (1 mole), 750 gms. dibutyltin oxide 1 (3 moles), 673 gms. propylene glycol dithioglycolate (3 8) O sn(OH3)2 S CHzCOOCHCHaCHZOOCOHZSH moles), 1,000 ml. of benzene, and 300 ml. of ethyl alcohol S CH 0060 H were stirred and heated under reflux until all the water of B-O 9P reaction was removed (for 3.5 hours). After the reaction O SI1(CH3)2OOCCH=OHCOOOHZCBHE was complete, the reaction mixture was filtered, and the For comparison, the previously mentioned known lf r solvents were distilled off under reduced pressure to give type stabilizer (14) was used. Three parts of each of the Compound! these two classes of stabilizers were added respectively to 100 parts by weight of PVC in which had been admixed 0 s (),H,) s CHzOO 0611011301120 0 O OHZSH 5% by weight of a styrene-acrylonitrile copolymer. The

1 BOS H mixtures were then mllled for 5 minutes on a mixing roll m S OHZCOOCHC HaoHzOOCCHZSH at 160:2" C. and made into sheets. The same tests for O 'SH(C4HD)2S oHioooorron omoooornsn resistance to heat and light, as described in Examples 1-14, were conducted with the results shown in Table IV. The yield of the product was 1,385 gms. (98.9%).

TABLE IV Resistance to heat test after- Resistance Stabilizer to light test (formula) 0.5 hr. 1.0 hr. 1.5 hrs. 2.0 hrs. after 48 hrs.

(18) Colorless Colorless Light yell0w Light yellow Colorless. (14) do Light yell0w. Yellow Light brown Brown.

*Control.

In the volatility test in which the changes in weight were measured after heating the stabilizers for 1 hour in a Geer oven at 180 C. the decrease in weight of stabilizer (18) was 0.2% whereas that of stabilizer (14) was 3.0%.

EXAMPLES 21-22 One mole of boric acid, 3 moles of diphenyltin oxide,

1 mole of thioglycollic acid and 1 mole of maleic acid were EXAMPLE 24- the reaction mixture was filtered, and the solvents were distilled off under reduced pressure to give the compound:

OSn(CHa)2-S omoooomornoooomsn BOSn(CH )2S CHzCOOCHzCHzOOCCHzSH O-Sn(CH )z-'0CCH=CHCOOC1sHaa The yield of the product was 1,200 gms. (97.3%

EXAMPLE 25 62 gms. boric acid (1 mole), 1,083 grns. dioctyltin oxide (3 moles), 210 gms. ethylene glycol dithioglycolate (1 mole), 202 gms. lauryl mercaptan (1 mole), 200 gms. lauric acid (1 mole), 1,000 ml. of benzene, and 300 ml. of ethylene alcohol were stirred and heated under reflux until all the water of reaction was removed (for 3.5 hours). After the reaction was complete, the reaction mixture was filtered, and the solvents were distilled off under reduced pressure to give the compound:

O-SI1(CgHl7)2-"SCHZCOOCHZCHZOOCCH2SH BOS 11(CsH11)2-S 012 25 OSn(CaH1 )z0OCCnH23 The yield of the product was 1,648 gms. (98.5%).

EXAMPLE 26 62 gms. boric acid (1 mole), 750 gms. dibutyltin oxide (3 moles), 202 gms. mercaptopropionic acid (1 mole), 92 gms. thioglycollic acid (1 mole), 144 gms. octyle acid (1 mole), 1,000 ml. of benzene, and 300 ml. of ethyl alcohol were stirred and heated under reflux until all the water of reaction was removed (for 3 hours). After the reaction was complete, the reaction mixture was filtered, and the solvents were distilled ofI under reduced pressure to give the compound:

The yield of the product was 1,110 gms. (95.2%

EXAMPLE 28 62 gms. boric acid (1 mole), 867 gms. diphenyltin oxide (3 moles), 176 gms. monomercaptoethyl maleate (1 mole), 116 gms. maleic acid (1 mole), 1,000 ml. of benzene, and 300 ml. of ethyl alcohol were stirred and heated under reflux until all the water of reaction was re moved (for 3 hours). After the reaction was complete, the reaction mixture was filtered, and the solvents were distilled off under reduced pressure to give the compound:

The yield of the product was 1,094 gms. (96.2%

EXAMPLE 29 62 gms. boric acid (1 mole), 876 gms. diphenyltin oxide (3 moles), 404 gms. mercaptopropionic acid (2 moles), 1,0 00 ml. of benzene, and 300 ml. of ethyl alcohol were stirred and heated under reflux until all the water of reaction was removed (for 3.5 hours). After the reaction was complete, the reaction mixture was filtered, and the solvents were distilled off under reduced pressure to give the compound:

(7) B-OSn(CsHs)2SCH2 8H. OSn(C@H )zOC )O The yield of the product was 1,207 gms. (96.0%).

EXAMPLE 30 62 gms. boric acid (1 mole), 750 gms. dibutyltin oxide (3 moles), 606 gms. mercaptopropionic acid (3 moles), 1,000 ml. of benzene, and 300 ml. of ethyl alcohol were stirred and heated under reflux until all the water of reaction was removed (for 3 hours). After the reaction was complete, the reaction mixture was filtered, and the solvents were distilled off under reduced pressure to give the compound:

EXAMPLE 31 62 gms. boric acid (1 mole), 750 gms. dibutyltin oxide (3 moles), 528 gms. monomercaptoethyl maleate (3 moles), 1,000 ml. of benzene, and 300 ml. of ethyl alcohol were stirred and heated under reflux until all the water of reaction was removed (for 3 hours). After the reaction was complete, the reaction mixture was filtered, and the solvent-s were distilled off under reduced pressure to give the compound:

OSn(O Hg)z-OOCCH=CHOOOCH2OH2SH The yield of the product was 1,203 gms. (95.8%).

EXAMPLE 32 62 gms. boric acid (1 mole), 750 gms. dibutyltin oxide (3 moles), 210 gms. ethylene glycol dithioglycolate (1 mole), 92 gms. thioglycollic acid (1 mole), 1,000 ml. of benzene, and 300 ml. of ethyl alcohol were stirred and heated under reflux until all the water of reaction was removed (for 3.5 hours). After the reaction was complete, the reaction mixture was filtered, and the solvents were distilled off under reduced pressure to give the compound:

The yield of the product was 1,003 gms. (97.4%).

EXAMPLE 33 62 gms. boric acid (1 mole), 750 gms. dibutyltin oxide (3 moles), 473 gms. dimercaptoethyl maleate (2 moles), 200 gms. lauric acid (1 mole), 1,000 ml. of benzene, and 300 ml. of ethyl alcohol were stirred and heated under reflux until all the water of reaction was removed (for 3 hours). After the reaction was complete, the reaction mixture was filtered, and solvents were distilled off under reduced pressure to give the compound:

OSn(O I-I )z-S OHzOHzOOCOH=CHCOOOH2OH2SH (15) B-O-Sn(C Hv)zS CHzOH2OOCCH=OHOO o OHzCHzS H O-S 11(C Ho)20 O 0111123 The yield of the product was 1,350 gins. (96.4%).

'EXAMPLE 34 '62 gms. boric acid (1 mole), 1,083 gms. dioctyltin oxide (3 moles), 210 gms. ethylene glycol dithioglycolate (1 mole), 404 gms. dodecyl tnercaptide (2 moles), 1,000 ml. of benzene, and 300 ml. of ethyl alcohol were stirred and heated under reflux until all the water of reaction was removed (for 3.5 hours). After the reaction was complete, the reaction mixture was filtered, and the solvents were distilled 011 under reduced pressure to give the compound:

O--SI1(C5H17)2S CHzCOOCHzCHzOOCCHzSH BOSn(CsH17)zS C1zH25 OSn(Ca 11)2 0121125 The yield of the product was 1,650 gms. (98.5%).

EXAMPLE 35 62 gms. boric acid (1 mole), 495 gms. dimethyltin oxide (3 moles), 224 gms. propylene glycol dithioglycolate (1 mole), 206 gms. benzyl maleate (1 mole), 200 gms. lauric acid (1 mole), 1,000 ml. of benzene, and 300 ml. of ethyl alcohol were stirred and heated under reflux until all the water of reaction was removed (for 3.5 hours). After the reaction was complete, the reaction mixture was filtered, and the solvents were distilled off under reduced pressure to give the compound:

OSD.(OH3)ZS 01120 O O CHCH3CH2O O C CHzS H BOSn(OHa)2-O O OCnH2a OSn(CH )z-OOCCH=CHOOOOH C H The yield of the product was 1,090 gms. (98.8%).

EXAMPLE 36 62 gms. boric acid (1 mole), 867 gms. diphenyltin oxide (3 moles), 92 gms. thioglycollic acid (1 mole), 98 gms. maleic anhydride (1 mole), 1,000 ml. of benzene, and 300 ml. of ethyl alcohol were stirred and heated under reflux until all the water of reaction was removed (for 3 hours). After the reaction was complete, the reaction mixture was filtered, and the solvents were then distilled off under reduced pressure to give the compound:

OSn(C H -OOCCH The yield of the product was 988 gms. (95.5%

Although this invention has been illustrated by reference to specific embodiments, modifications thereof which are clearly within the scope of the invention will be apparent to those skilled-in-the-art.

We claim:

1. A stabilized polyvinyl chloride resin composition comprising essentially, in a predominant amount, a polyvinyl chloride resin and, in a small amount, at least one boron-containing organotin compound having the formula wherein R is a member selected from the group consisting of alkyl, and aryl; X X and X are independently selected from the group consisting of I SR wherein R. R and R" are selected from the group consisting of alkyl, alkenyl, aryl, aralkyl, and alkaryl such that at least one of X exhibits a free sulfhydryl radical such that when any one of said X substituents is divalent only two X substituents are present in said compound.

2. A polyvinyl chloride resin composition as defined in claim 1 wherein an amount of the boron-containing organotin compound is 0.1-10 parts by weight based on parts by weight of polyvinyl chloride resing.

3. A polyvinyl chloride resin composition as defined in claim 1, wherein the boron-containing organotin compound is 4. A polyvinyl chloride resin composition as defined in claim 1, wherein the boron-containing organotin compound is 5. A polyvinyl chloride resin composition as defined in claim 1, wheerein the boron-containing organotin compound is 6. A polyvinyl chloride resin composition as defined in claim 1, wherein the boron-containing organotin compound is 7. A polyvinyl chloride resin composition as defined in claim 1, wherein the boron-containing organotin compound is References Cited UNITED STATES PATENTS 2,904,570 9/ 1959 Ramsden 260--429.7 3,003,999 10/1961 Kauder 26045.75 3,284,383 11/1966 Proops 260--18 DONALD E. CZA'J A, Primary Examiner V. P. HOKE, Assistant Examiner U.S. Cl. X.R. 260-23, 414, 429.7 

